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The “Recommended Practices for Maintaining a Sterile Field” has been reviewed and revised by the Recommended Practices Committee. These recommended practices are being presented for public review and comment. The comment period will close March 25, 2005. Go to www.aorn.og and click the "Comments" link at the bottom of the page to leave comments.

Recommended Practices for Maintaining a Sterile Field

The following proposed recommended practice for maintaining a sterile field was developed by the AORN Recommended Practices Committee. It is being presented for review and comment at this time. The AORN Recommended Practices Committee is interested in receiving comments on this proposal from members and others.

These recommended practices are intended as achievable recommendations representing what is believed to be an optimal level of practice. Policies and procedures will reflect variations in practice settings and/or clinical situations that determine the degree to which the recommended practices can be implemented.

AORN recognizes the numerous settings in which perioperative nurses practice. These recommended practices are intended as guidelines adaptable to various practice settings. These practice settings include traditional operating rooms, ambulatory surgery centers, physicians’ offices, cardiac catheterization suites, endoscopy suites, radiology departments, and all other areas where operative and other invasive procedures may be performed.

Purpose:

These recommended practices provide guidance for establishing and maintaining a sterile field. The creation and maintenance of a sterile field can directly influence patient outcomes. Adherence to aseptic practices by all individuals involved in surgical interventions aids in fulfilling the professional responsibility to protect patients from injury. Aseptic practices are implemented preoperatively, intraoperatively, and postoperatively to minimize wound contamination and reduce patient risks for surgical site infections.

Perioperative Nursing Vocabulary

The perioperative nursing vocabulary is a clinically relevant and empirically validated standardized nursing language. This standardized language consists of the Perioperative Nursing Data Set ( PNDS ) and includes perioperative nursing diagnoses, interventions, and outcomes. 1 The expected outcome of primary importance to this recommended practice is outcome O10, “The patient is free from signs and symptoms of infection.” This outcome falls within the domain of Physiological Responses (D2). The associated nursing diagnosis is X28: “Risk for infection.” The associated interventions that may lead to the desired outcome may be I21: “Assesses susceptibility for infection”; I70: “Implements aseptic technique”; and I98: “Protects from cross-contamination.”

RECOMMENDED PRACTICE I

Scrubbed persons should function within a sterile field.

1. Before donning sterile gowns and gloves, surgical hand antisepsis should be performed according to AORN’s “Recommended practices for surgical hand antisepsis/hand scrubs” 2 and the manufacturer’s written instructions for the antiseptic. Surgical hand antisepsis decreases the microbial counts on the skin and will reduce the transfer of microorganisms.

2. Personnel within the sterile field should wear scrub attire, caps, masks, and sterile gowns and gloves to prevent microbial transference to the sterile field, surgical site, and patient during the surgical procedure. 3-6

3. Scrubbed personnel should don sterile gowns and gloves from a sterile area away from the main instrument table to prevent contamination of the sterile field. 7-11

4. Materials for gowns should be selected according to AORN’s “Recommended practices for selection and use of surgical gowns and drapes” 12 and according to the required level of barrier protection as outlined in the Association for the Advancement of Medical Instrumentation’s (AAMI’s) PB70 “Liquid barrier performance and classification of protective apparel and drapes intended for use in health care facilities.” 13 Surgical gowns should be of sufficient size to adequately cover the scrubbed person. Surgical gowns should establish a barrier that minimizes the passage of microorganisms between nonsterile and sterile areas. 11, 14

5. The front of sterile gowns are considered sterile from the chest to the level of the sterile field. The sterile area of the gown front extends to the level of the sterile field because most scrubbed personnel work adjacent to a sterile bed and/or table. Gown sleeves are considered sterile from two inches above the elbow to the cuff, circumferentially.

The neckline, shoulders, underarms, sleeve cuffs, and gown back are areas o f f riction and, therefore, are not considered effective microbial barriers. The gown back is considered nonsterile because it cannot be constantly monitored.

Gowns of an adequate size to close completely in the back and a sleeve length adequate to prevent cuff exposure outside the glove should be selected.

6. Sleeve cuffs should be considered contaminated when the scrubbed person’s hands pass beyond the cuff. 8, 9,11

a. Cuffs of the gown should remain at the natural wrist area.

b. Gowns should not be pulled up leaving cuffs exposed.

c. Sleeves of the gown should be of sufficient length and should cover the back of the hand to avoid exposing the gown cuff when the gloves slide down.

7. Scrubbed personnel should inspect gloves for integrity after donning them. Intact gloves establish a barrier that minimizes the passage of microorganisms between nonsterile and sterile areas. 3, 11,15 AORN’s “Recommended practices for standard and transmission-based precautions” 16 should be followed. Policies and procedures in the practice setting should indicate when double-gloving is required to reduce the potential for hand contact with blood and body fluids.

8. Sterile gloves that become contaminated should be changed as soon as possible. The preferred method to change gloves is assisted gloving whereby one member of the sterile team assists another member. This technique allows a gowned and gloved team member to touch only the outside of the new glove when applying the glove to a team member’s hand. If this method is not possible, the contaminated glove should be changed by the open-glove method. If it is not possible to change the glove at the moment the break in technique is noted, a new glove may be donned over the contaminated/damaged glove until it can be changed. 8,10,11

RECOMMENDED PRACTICE II

Sterile drapes should be used to establish a sterile field.

1. Surgical drapes should be selected according to AORN’s “Recommended practices for selection and use of surgical gowns and drapes” 12 and the AAMI guideline “Liquid barrier performance and classification of protective apparel and drapes intended for use in health care facilities.” 13 Surgical drapes should establish an aseptic barrier that minimizes the passage of microorganisms between nonsterile and sterile areas. 14, 17, 18

2. To prevent transfer of microorganisms from nonsterile to sterile areas, sterile drapes should be placed on the patient, furniture, and equipment to be included in the sterile field. 18,19

3. Sterile drapes should be handled as little as possible. Rapid movement of draping materials creates air currents on which dust, lint, and other particles can migrate. 10, 20, 21

4. Draping material should be held in a compact manner, held higher than the OR bed, and placed from the surgical site to the periphery to minimize contamination of the surgical site. Some procedures may require modified draping techniques (eg, extremities). 8, 9, 11

5. During draping, gloved hands should be protected by cuffing the drape material over the gloved hands to reduce the potential for contamination. 8, 9, 11

6. The portion of the surgical drape that establishes the sterile field should not be moved after it is positioned. Shifting or moving the sterile drape can compromise the sterility of the field. 8, 9, 11

RECOMMENDED PRACTICE III

Items used within the sterile field should be sterile.

1. To ensure that only sterile items are presented to the sterile field, all items should be inspected immediately before presentation to the field for proper packaging, processing, seal, package container integrity, and inclusion of a sterilization indicator that has changed color demonstrating that sterilization parameters were met. If an expiration date is provided, the date should be checked before opening the package and delivering the contents to the field. Outdated items should not be used. 11, 22

An event-related sterility system should be used and is based on the concept that “sterility is not altered over time, but may be compromised by certain events or environmental conditions.” 23 Shelf life refers to the time an item may remain on the shelf and still maintain its sterility. Shelf life is influenced by the type of packaging used, storage conditions (eg, open or closed shelves), humidity, temperature, transport conditions, use of dust covers, and the amount of handling the item receives. 11, 22, 23

Spaulding’s criteria are used to determine the potential for transmission of infectious agents.(reference) Within this classification, items contacting the vascular system, the neurological system, and/or sterile tissues pose the greatest risk of infection and are classified as critical items. Using sterile items when contacting sterile tissues minimizes the risk of infection. 11, 24-28

2. Packaging materials should meet the criteria identified in AORN’s “Recommended practices for selection and use of packaging systems.” 29

3. Methods of sterilization, event-related shelf life, and handling of sterile items should be in accordance with AORN’s “Recommended practices for sterilization in perioperative practice settings.” 30 Sterilization provides the highest level of assurance that surgical items are free of viable microbes. High-level disinfection reduces the risk of microbial contamination, but it does not ensure the same margi n of safety that sterilization provides. 24, 26, 28, 31

RECOMMENDED PRACTICE IV

All items introduced to a sterile field should be opened, dispensed, and transferred by methods that maintain item sterility and integrity.

1. All invasive surgical procedures should have sterile instruments and supplies, and the surgical team should practice careful aseptic technique for all surgical patients.

There is no such thing as “clean” and “dirty” procedures when it comes to aseptic technique. Although the mucous membranes of the mouth and the urinary and intestinal tracts are an effective bacterial barrier when intact, ear, nose, and throat procedures; cystoscopy; hemorrhoidectomy, and other procedures are invasive and impair the integrity of the mucosal barrier. The normal flora of the mouth is not infectious to the individual in question, but it may be pathogenic when transferred to other tissues by contaminated surgical instruments.

Hospital-acquired surgical infections are a leading cause of patient morbidity and mortality in the United States . Rigorous adherence to the principles of asepsis is the foundation of surgical site infection prevention, and it should never be circumvented to save time or money. A sterile field should be prepared and maintained for every surgical patient. 3, 21, 24

2. Unscrubbed individuals should open wrapped sterile supplies by opening the wrapper flap farthest away from them first to prevent contamination by passing an unsterile arm over a sterile item. Next, open each of the side flaps. The nearest wrapper flap should be opened last. 8-10, 19

3. All wrapper edges should be secured when supplies are presented to the sterile field. Securing the loose wrapper edges prevents them from contaminating the sterile field. 8, 9

4. Sterile items should be presented to the scrubbed person or placed securely on the sterile field. Items tossed onto a sterile field may roll off the edge, create a hole in the sterile drape, or cause other items to be displaced, leading to contamination of the sterile field. 8, 9

a. Sharps and heavy objects should be presented to the scrubbed person or opened on a separate surface. These heavy items may penetrate the sterile barrier if dropped onto the sterile field. 8, 9

b. Peel pouches should be presented to the scrubbed person to prevent contamination of the contents.

c. Rigid container systems should be opened on a separate surface. The lid should be lifted toward the person opening the container and away from the container. The filter should be checked and changed according to the manufacturer’s written instructions.

5. All items should be delivered to the surgical field in a manner that prevents nonsterile objects or people from extending over the sterile field. Skin is a source of bacteria and scurf shedding; therefore, maintaining distance from the sterile field can decrease the potential for contamination when items are passed from an unsterile to a sterile area. 8,9,19

6. When dispensing solutions, the solution receptacle on the sterile field should be placed near the table’s edge or held by the scrubbed person. The entire contents of the container should be poured slowly to avoid splashing. Splashing can cause strike-through and splash-back from nonsterile surfaces to the sterile field. Placing the solution receptacle near the edge of the sterile table allows the unscrubbed person to pour fluids without contaminating the sterile field. Any remaining fluids should be discarded. The edge of a container is considered contaminated after the contents have been poured; therefore, the sterility of the contents cannot be ensured if the cap is replaced. Reuse of open containers may contaminate solutions due to drops contacting unsterile areas and then running back over container openings. 8, 9

7. Medications should be delivered to the sterile field in an aseptic manner. Stoppers should not be removed from vials for the purpose of pouring medications. Sterile transfer devices (eg, sterile vial spike, filter straw, plastic catheter) should be used to dispense medications to the sterile field. Medications should be delivered to the sterile field according to AORN’s “Recommended practices for hazards in the surgical environment,” 32 the AORN Guidance Statement “Safe medication practices in perioperative practice settings,” 33 and the policies and procedures of the practice setting.

RECOMMENDED PRACTICE V

A sterile field should be maintained and monitored constantly.

1. The sterile field should be prepared in the location in which it will be used. Moving tables stirs air currents that can contaminate the sterile field. 20, 34

2. Open sterile supplies should only be exposed to one patient at a time. Opening several cases in a room at one time exposes the sterile field to more than one patient. The first patient receives sterile items that have not been exposed to any other patient. Future patients receive items exposed to a variety of infected and noninfected patients, as well as to increased movement and traffic in the OR. 24, 28

A concurrent case in the same room also exposes patients to a variety of hazards and increases the risk of contamination and infection. The transmission of infectious diseases can occur by airborne, contact, and droplet methods. The risk of cross-contamination may be increased significantly when two sterile fields, two surgical teams, and two open surgical wounds are confined to one OR. Operating rooms in the United States are not designed to accommodate the additional personnel and equipment necessary to care for two patients simultaneously. In the United States , general ORs built to American Institute of Architects (AIA) standards are 400 sq ft. 35 Some ORs may even be as small as 360 sq ft. This square footage minimum is intended to accommodate the equipment and personnel necessary for one surgical field. For unsterile personnel, such as the circulator, to move around the sterile field without contaminating it, he or she should maintain a distance of at least 12 inches from the sterile field. When two patients and two sterile fields occupy an area designed to accommodate one patient and one sterile field, contamination of the sterile field is likely.

3. Sterile fields should be prepared as close as possible to the time of use. The potential for contamination increases with time because dust and other particles present in the ambient environment settle on horizontal surfaces over time. Particulate matter can be stirred up by movement of personnel when opening the room and also can settle on opened sterile supplies. 3, 20, 21, 34, 36, 37

There is no specified amount of time designated that a room can remain open and not used and still be considered sterile. The sterility of an open sterile field is event-related. An open sterile field requires continuous visual observation. Direct observation increases the likelihood of detecting a breach in sterility. 37, 38

4. Sterile fields should not be covered. Although there are no research studies to support or discount the practice, removing a table cover may result in a part of the cover that was below the table level being drawn above the table level or air currents drawing microorganisms from a nonsterile area to the sterile field. It is important to continuously monitor all sterile areas for possible contamination. 20

5. Conversations in the presence of a sterile field should be kept to a minimum to reduce the spread of droplets. Air contains microorganisms on airborne particles, such as respiratory droplets. The primary source of airborne bacteria is health care personnel. 6,11,28,39

6. Surgical equipment (eg, cables, tubing) should be secured to the sterile field with nonperforating devices. Perforations in a barrier provide portals of entry and exit for microorganisms, blood, and other potentially infectious body fluids.

7. Nonsterile equipment (eg, Mayo stands) should be covered with sterile barrier material(s) before being introduced to or brought over a sterile field. Only sterile items should touch sterile surfaces. The Mayo stand should be covered with a barrier material on the top, bottom, and all sides. Sterile barrier material also should be applied to the portion of the Mayo stand or other equipment that will be positioned immediately adjacent to the sterile field. 10

RECOMMENDED PRACTICE VI

All personnel moving within or around a sterile field should do so in a manner that maintains the sterile field.

1. Scrubbed personnel should remain close to the sterile field. 8, 9 Walking outside the sterile field’s periphery or leaving the OR in sterile attire increases the potential for contamination. Using a closed container system for flash sterilization and transport of items eliminates the need for the scrubbed person to leave the sterile field and retrieve instruments from a sterilizer.

2. Scrubbed personnel should move from sterile areas to sterile areas to prevent contamination. If they must change position, they should turn back to back or face to face while maintaining safe distances from each other and the sterile field.

3. Unscrubbed personnel should face sterile fields on approach, should not walk between two sterile fields, and should be aware of the need for distance from the sterile field. By establishing patterns of movement around the sterile field and keeping sterile areas in view, accidental contamination can be reduced.

4. Scrubbed personnel should keep their arms and hands above the level of their waist at all times. Hands should be clasped in front of the body above waist level.

Contamination may occur when arms and hands are moved below waist level. Arms should not be folded with the hands in the armpits. This area has the potential to become contaminated by perspiration allowing for strike-through of the gown and, ultimately, contamination of the gloved hands. The armpit also is an area o f f riction and, therefore, is not considered an effective microbial barrier.

5. Scrubbed personnel should avoid changing levels and should be seated only when the entire surgical procedure will be performed at that level. When changing levels, exposure of the nonsterile portion of the surgical gown is likely.

6. The number and movement of individuals involved in a surgical procedure should be kept to a minimum per AORN’s “Recommended practices for traffic patterns in the perioperative practice setting.” 34 Bacterial shedding increases with activity. Air currents can pick up contaminated particles shed from patients, personnel, and drapes and distribute them to sterile areas. 11,21,28,40

7. When a break in sterile technique occurs, corrective action should be taken immediately unless the patient’s safety is at risk. If the patient’s safety is at risk, correct the break in technique as soon as it is safe to do so.

8. When a break in sterile technique occurs and cannot be corrected immediately, it should be recorded on a form internal to the organization, such as an incident/occurrence report, and the wound classification should be adjusted accordingly and documented on the operative record.

RECOMMENDED PRACTICE VII

Policies and procedures for maintaining a sterile field should be developed, reviewed periodically, revised as necessary, and readily available in the practice setting .

1. Policies and procedures for maintaining a sterile field should be developed by each facility and should include, but not be limited to,

monitoring of environmental conditions, including OR air exchange rate and pressure, temperature, and humidity.

3. These recommended practices should be used as guidance for developing policies and procedures in the perioperative practice setting. Policies and procedures serve as operational guidelines and establish authority, responsibility, and accountability within the facility.

4. Personnel should be knowledgeable about the procedures involved in developing and maintaining a sterile field. An introduction and review of policies and procedures for maintaining the sterile field should be included in orientation to the perioperative setting. Continuing education should be provided when new technologies (eg, sterilization containers, barrier materials) are introduced. Ongoing education of perioperative personnel will facilitate the development of knowledge, skills, and attitudes that affect surgical patient outcomes. Policies and procedures also assist in the development of quality assessment and improvement activities.

GLOSSARY

Asepsis : Process for keeping away disease-producing microorganisms.

Aseptic technique : Methods by which contamination with microorganisms is prevented.

Closed gloving method : Used when wearing a sterile gown to prevent exposure of bare skin during gowning and donning of sterile gloves, thereby lessening the chance of contamination.

Critical Items : An item that contacts the vascular system or enters sterile tissue, posing the highest risk of transmission of infection.

Event-related Sterility: Shelf life of a packaged sterile item depends on the quality of the wrapper material, the storage conditions, the conditions during transport, and the amount of handling.

Non-critical Items : An item that comes in contact with intact skin but not with mucous membranes, sterile tissue, or the vascular system.

Open-gloving method : Used when changing a glove during a surgical procedure. A method of donning sterile gloves in which the everted cuff of each glove allows the gowned person to touch the inner side of the glove with ungloved fingers and the outer side of the glove with gloved fingers.

Semi-critical Items : An item that comes in contact with mucous membranes or with skin that is not intact.

Sterile : The absence of all living microorganisms.

Sterile Field : Area around the site of the incision into tissue or the site of introduction of an instrument into a body orifice that has been prepared for the use of sterile supplies and equipment. This area includes all furniture covered with sterile drapes and all personnel who are properly attired in sterile garb.

Sterile technique : Methods by which contamination with microorganisms is prevented to maintain terility throughout the surgical procedure.

Sterilization : Processes by which all pathogenic and nonpathogenic microorganisms, including spores, are killed.

Strike-through : Contamination of a sterile surface by moisture that has originated from a nonsterile surface and penetrated the protective covering of the sterile item.

Time-related Sterility : Expiration dates are established to indicate the duration of time within which a sterile item is considered sterile and safe to use.

14. J Lister, “Original Communications,” in Demonstrations of Antiseptic Surgery before members of the British Medical Association, in the Operating Theatre of the Royal Infirmary, 4 th and 5 th August 1875.